Treating sludge acid



F. M. ROGERS ET AL May 24, `1927.

TREATING AsL-UDGE ACID Filed Aug. 14Y 1924 Patented May 24, 1927.

UNITED STATES PATENT OFFICE.;

FRANCIS M. ROGERS AND FRANK V. GRIM M, OF WHITING, INDIANA, AND GERALDIL.

WENDT, F CHICAGO, ILLINOIS, ASSIGNORS T0 STANDARD OIL COMPANY, OF WHIT- ING, INDIANA, A CORPORATION 0F INDIANA.

'mirarme SLUDGE Aon).

Application led August 14, 1924. Serial No. 731,995.

The present application relates to improvements in the concentration of sludge acids and similar products and will be fully understood from the following description,

'5 illustrated by the accompanying drawing, in which apparatus for carrying the 1nvention into eliect is diagrammatically shown in plan. l f A Sludge acid, w uch in ordinary refinery practice may be derived from the sulfuric acid-.treatment of a single type oi oil or may be a mixed product from the acid treatment oi': several types of oil, contains substantial proportions ofy organic matter. which remain in the acid even after dilution by water or by weaker sludge acids to the lowestconcentration which 'may be economically concentrated for reuse. In ordinary lpractice thesludge acid may be diluted, for example to 35 to 42 Baume, an average sludge acid, ready for reconcentration, being 37 to 38 Baume. The sludge acid, even when soA diluted, contains sufficient organic matter to give a carbon content of 0.8 to 1% or higher. The organic matter thus present in the sludge' acid gives rise to a consider- Vable loss of acid during concentration as well as introducing diculties in operation,

particularly when pan-concentration 'meth-l ods are employed.

.In accordance with the present invention, the organic matter present in the sludge acid is materially reduced or may be even substantially eliminated by subjecting the acid, prior to concentration, to electrolysis by any suitable means.` In the drawing, means are shown diagrammatically in plan whereby the operation may be carried out continuously. In the figure the numeral 5 represents a vertical electrolyzing chamber, which may suitably'be constructed of lead or bronze (or, in large scale operation, may beV lead-lined) and provided with vertical baiiles 6 extending alternately from opposite sides of the receptacle-partly across it. The `sludge acid to be treated enters by means of the inlet pipe 7 and makes its exit at the opposite end of the receptacle through the outlet pipe 8. In passing through the electrolyzing receptacle, it is forced by the baiiles 6 to travel an extended route. `At

suitable distances from the batlies 6 and from the walls of the receptacle 5, the electrodes 9 are supported within the electrolyzing chamber. The electrodes 9 are connected to a common conductor 10 leading to `oue pole of a suitable source of current, and the body of the receptacle 5 with which the batlles 6v are in conductive contact, is connected by conductor 11 with the opposite pole of a current source. It is to be clearly understood, of course, that any desired form of electrolyzing apparatus, either batch or continuous, may be employed and that the.,

form illustrated is not intended to limit the character of the invention herein described and claimed.,

By electrolysis of the sludge acid, the organic matter present is largely or completely removed, according to the extent to which the electrolysis is conducted. The actlon appears to consist largely in oxidation, and to some extent, in a coagulation of'the organic matter, which is carried' to the surface of the acid by the rising gas bubbles and forms 'a dark colored scum thereupon. In general it is suilicient to carry the electrolysis to a point such that the carbon content of the acid does not.ex ceed 0.4% although, if desired, by longer continued action, the organic matterv can pe reduced to .a carbon coutent of 0.2% or ower.'

In carrying out the invention, the sludge acid to be treated, and derived from various refinery sources, is diluted to 35 to 45o Baume by the addition of Water or of Weaker sludge acids. The removal of the organic matter bythe electrolytic process is found and preferably decimeter has been found suit-able, from 3 to 3.5 amperes being preferred, Theelectrolysis of the sludge acid is carried to a suiicient extent to bring the organic matter present to below 0.4%` carbon, as in general a further reduction is uneconomical. If

desired, however, the' electrolysis ma, be continued until the carbon content o the acid is reduced to 0.2% or lower.

'We claim: y

1. The method of removing organic matter from refinery sludgev acids which comprises passing an electric current therethrough to form elementary oxygen. and hydrogen by dissociation, thereby effecting .oxidation of organic matter and causing the same to be raised to the surface of the treated acid by the action ofthe released gases, and separating the organic matter;

2. The method of removing organic matter from refinery sludge acids-which comprises heating such acid to above 100 F., passing an .electric current therethrough to form elementary oxygen and hydrogen, thereby effecting oxidation of organic matter and causing the same to be raised to the surface of the treated acid by the action of the released gases.

3. The method of removing organic matter from refinery sludge acidA comprising diluting such cid to 35 to 45 Baume, and sub'ecting the diluted acid to electrolysis wit a current density of 1.5 to 5 amperes per s uare decimeter.

4. he method of removing organic matter from refinery sludge acid which comprises diluting vsuch acid to 35 to 45 Baume, heating the diluted acid to about 150 F. and subjecting it to electrolysis with a. current density of 3 to 3.5 amperes per square decimeter and continuing the electrolysis until the carbon content of the acid is reduced to below 0.4% carbon.

5. The method of treating refinery sludge acid which comprises bringing such acid to a specific gravity of 35 to 45 Baume, preheating it to above 100 F., then subjecting it to electrolysis to a. reduction of the carbon content to less than 0.4% and subsequently concentrating the treated sludge acid.

FRANCIS M. ROGERS. FRANK V. GRIMM. GERALD L. WENDT. 

